Transmitter.



C. A. RETFEL.

1 TRANSMITTER.

APPLICATION FILED Nov. 1o. |91?.

iiz@ Patented sept. 10,1918.

wir/1158853 /f/yffvae @Ama-fe@ CHARLES ANDREW REIFEL, OF NEW YORK, N. Y.

TRANSMITTER.

Specification of Letters Patent.

lPatented Sept. Mb, 1918.

Application filed November 10, 1917. Serial No. 201,317.

T all whom it may concern.'

lie it known that I, CHARLES A. REIFEL, a-

citizen of the United States, and a residentl ot' the city of New `York, borough of Manhattan, in the county and State of New York, have invented a new and Improved Transmitter, of which the following is a t'ull, clear, and exact description.

This invention relates to sound transmitters of the microphone type especially adapted for use in audiphones and similar instruments.

The invention has for its general objects to provide a transmitter of improved Construction whereby the sensitiveness is in creased and sounds transmitted wit-h 'fullness and loudness of tone while the tnnsmitter is oi minimum size.

more specific object of the invention is the provision oi a sound box or resonant chamber formed .in the body or shell ot the device, whereby the range of effectiveness is increased and a more natural tone produced with fullness and loudne'ss.

W'ith such objects in view, and others which will appear as the description proceeds, the invention comprises various novel features of construction and arrangement of parts which will be sel' forth with particularity in `the tollouim;r description and claims appended hereto.

ln the accomlmnving drawing, which illustrates one emoodiment ol the invention and wherein similar characters oi reference indicate corresponding parts in all the views,

Figure 1 ter;

a front vic-w of the transmit 2 is a central section; and lliflj. 3 is a front view ot the transmitter with the outer cap removed.

lcierringlo the drawinff. 1 designates the back of the transmitter which has removably applied thereto a cap Q. and clamped bctwceu the flange ol' the hack and annular shoulder 4got' thc rap 2 is a diaphrar'mf whirl; cooperates willi the usual microphone 5 in the back 1. The cap has a shallow aised portion 6 which Jforms a chamber 7 at. the side of the diaphragm opposite from the microphone. Fitted over the cap 2 is an outer cap 8 which cooperates with the inner cap Q to torni a. sound collecting chamber or resonant box 9. The face or wall 10 of the cap S is provided with apertures 11 by which the sound waves enter the chamber 9. By extensive experimenting it hasI been found that. best resuits are obtained by having` at the center ot the face 12 of the inner cap a group of closely arranged apertures 13 which iiare outwardly or toward the openings ll, whereby the sound waves pass into the chamber 7' and strike on the center of the dihphragin. It is dillicult to explain the theory by which the best results are obtained through arranging the apertures in the manner specified, but fuller -andlouder tones can be transmitted more naturally and the instrument is rendered more sensitive.

From `the foregoing description taken in connection with the accompanying drawing, the advantages or the construction and method ot operation will be readily understood by those skilled in the art to which the invention appertains, and while l have described the principle of operation, together with the device which l( now consider to be the bestV embodiment thereof, l desire to have it understood that the device shown is merelyy illustrative -and that such changes may be made when desired as fall within the scope ot' the appended claims.

Having' thus described my invention,

claim las new and desire to secure by Letters Patent:

l. transmitter ot` the ciass described in cludingg a diaphragm, a bark having a chainber. a riiicrophone in the chamber, an inner cap fitted to the back and clamping tbe dia.- phragrin in place, said cap'being formed with a chau'iber at the side ot the transmitter opv positc Yfrom the microghone. and an outer cap forming with the rst-mentioned cap a resonant chamber, there being a plurality of closely arranged apertures inthe central portion of cach cap 2. transmitter of the class described comprising a diaphragm, a microphone at one side ol the diaphrag: and a structure in which the diaphragm and microphone are mounted, said structure having a relatively shallow chamber at the side 0f the diaphragm opposite from the microphone,

and a deeper chamber outwardly from thev first-mentioned chamber and diaphragm, the Wall of the outer chamber being provided with a plurality of closely arranged soun'di verge outwardly toward the first-mentionedv apertures.

CHARLES ANDREW REIFEL. 

